Cylindrical nickel-hydrogen storage battery

Abstract

The invention is directed to provide a cylindrical nickel-hydrogen storage battery having high discharge power densities both at SOC 50% and at SOC 20%. In an alkaline storage battery according to an embodiment of the invention, a nickel positive electrode formed into a rectangular shape has a short side length of X and a long side length of Y, the ratio (Y/X) of the long side length to the short side length is 25 or more and 40 or less (25≦Y/X≦40), the short side length is 25 mm or more and 45 mm or less (25 mm≦X≦45 mm), and the battery capacity is 3 Ah or more and 7 Ah or less.

What is claimed is: 
     
         1 . A cylindrical nickel-hydrogen storage battery comprising:
 a spiral electrode group, the spiral electrode group including:
 a nickel positive electrode filled with a positive electrode active material and formed into a rectangular shape, 
 a negative electrode filled with a negative electrode active material and formed into a rectangular shape, and 
 a separator formed into a rectangular shape; 
   an alkaline electrolyte; and   a battery container storing therein the spiral electrode group and the alkaline electrolyte and sealed,   the nickel positive electrode formed into a rectangular shape having a short side length of X (mm) and a long side length of Y (mm), the ratio (Y/X) of the long side length to the short side length being 25 or more and 40 or less (25≦Y/X≦40), and the short side length being 25 mm or more and 45 mm or less (25 mm≦X≦45 mm), and   the cylindrical nickel-hydrogen storage battery having a battery capacity of 3 Ah or more and 7 Ah or less.   
     
     
         2 . The cylindrical nickel-hydrogen storage battery according to  claim 1 , wherein the nickel positive electrode is prepared by filling pores of a nickel sintered substrate with at least nickel hydroxide as a main positive electrode active material and zinc by impregnation treatment of an impregnation solution and alkaline treatment. 
     
     
         3 . The cylindrical nickel-hydrogen storage battery according to  claim 2 , wherein the zinc is contained in an amount of 8% by mass or less based on the nickel mass in the positive electrode active material, the alkaline electrolyte has an alkali concentration of 6.5 mol/L or less, and the alkaline electrolyte contains lithium (Li) in an amount of 0.3 mol/L or more. 
     
     
         4 . The cylindrical nickel-hydrogen storage battery according to  claim 2 , wherein the zinc is contained in an amount of 8% by mass or less based on the nickel mass in the positive electrode active material, the alkaline electrolyte has an alkali concentration of 7.5 mol/L or less, and the alkaline electrolyte contains sodium (Na) in an amount of 0.4 mol/L or more and 5.3 mol/L or less and lithium (Li) in an amount of 0.3 mol/L or less. 
     
     
         5 . The cylindrical nickel-hydrogen storage battery according to  claim 1 , wherein the negative electrode active material is a rare earth-Mg—Ni hydrogen storage alloy (having a crystal structure such as a Ce 2 Ni 7  type, a CeNi 3  type, and a Pr 5 Co 15  type except for a CaCu 5  type) and contains no manganese (Mn) or cobalt (Co).